Focal spot size measurements with pinhole and slit for microfocus mammography units
- 1 May 1988
- journal article
- research article
- Published by Wiley in Medical Physics
- Vol. 15 (3) , 298-303
- https://doi.org/10.1118/1.596264
Abstract
Many mammography units now have microfocal spots ranging in size from 0.09 to 0.4 mm for magnification radiography. On site measurements of these focal spots are not possible without invasive procedures if National Equipment Manufacturers Association (NEMA) specifications are to be followed. This paper describes a method to perform such measurements expeditiously (1.5 h) and noninvasively. We describe how this method differs from NEMA test specifications, and report the test results of 22 units from ten manufacturers. Six of the focal spots were larger than the manufacturer''s specifications which were based on current NEMA standards. Emphasis is placed on the need for verifiable standards for mammography x-ray systems.This publication has 3 references indexed in Scilit:
- Focal-spot measurement: comparison of slit, pinhole, and star resolution pattern techniques.Radiology, 1987
- X-ray tube focal spot sizes: comprehensive studies of their measurement and effect of measured size in angiography.Radiology, 1982
- A Highly Accurate Focal Spot Camera—Laboratory and Field ModelRadiology, 1978